Mariana Mitru - 1 year ago 66
Java Question

# How can I make a border to a matrix in java?

I have this matrix :

So 2 line and 2 columns.

• 1 2

• 3 4

``````    for (int i = 0; i < m; i++) {
for (int j = 1; j < n; j++) {
try {//    System.out.println("number is ");
a[i][j] = scanner.nextInt();

} catch (java.util.NoSuchElementException e) {
// e.printStackTrace();
}
}
}         //print the input matrix
``````

How can I make a border to a matrix? I've seen that in java there is no index -1.

I want a border with a number. For example :
0 0 0 0

• 0 0 0 0

• 0 1 2 0

• 0 3 4 0

• 0 0 0 0

How should I make that border function?

First you need to create the matrix with extra rows and columns, for example in your case a 4x4 matrix. and them put 0 on the borders

when i==0 or i==n-1, j==0 or j==n-1,

``````int a[][] = new int[4][4];
int n,m;
n=4;
m=4;
for(int i=0;i<m;i++){
for(int j=0;j<n;j++){
if(i==0 || j==0 || i==m-1 || j==n-1){
//a[i][j] = 0;
a[i][j] = 1;
}
System.out.print(a[i][j]+" ");
}
System.out.println();
}
``````

then

``````for (int i = 1; i < m-1; i++) {
for (int j = 1; j < n-1; j++) {
try {//    System.out.println("number is ");
a[i][j] = scanner.nextInt();

} catch (java.util.NoSuchElementException e) {
// e.printStackTrace();
}
}
}         //print the input matrix
``````
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